MESOSCALE DISCUSSION 0589
NWS STORM PREDICTION CENTER NORMAN OK
0111 PM CDT TUE APR 26 2011
AREAS AFFECTED...NORTHEAST TX AND FAR SOUTHEAST OK/NORTHERN
LA/SOUTHERN AR
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY
VALID 261811Z - 262015Z
THE SEVERE THREAT IS EXPECTED TO STEADILY INCREASE THROUGH MID/LATE
AFTERNOON...INITIALLY ACROSS PORTIONS OF NORTHEAST TX AND INTO
SOUTHEAST OK/NORTHERN LA/SOUTHERN AR. A RELATIVELY LONG LEAD
TIME/DURATION PARTICULARLY DANGEROUS SITUATION /PDS/ TORNADO WATCH
WILL LIKELY BE ISSUED BY MID AFTERNOON.
WITH SURFACE CYCLOGENESIS UNDERWAY ACROSS THE SOUTHERN HIGH
PLAINS...THE WARM SECTOR AIRMASS...EAST OF A NEAR I-35 CENTRAL TX
DRYLINE...AND ALONG/SOUTH OF A SLOW NORTHWARD-RETURNING
SOUTHWEST-NORTHEAST ORIENTED FRONTAL BOUNDARY FROM THE SOUTH DFW
METRO INTO SOUTHERN AR...HAS ALREADY BECOME MODERATE TO STRONGLY
UNSTABLE IN THE PRESENCE OF LITTLE CINH. AFTER A BRIEF BOUT OF
SHORTWAVE RIDGING AT MIDDAY...THE LEADING EDGE OF AN UPPER JET
STREAK APPEARS TO HAVE REACHED THE SOUTHERN HIGH PLAINS...WITH
LIKELY-ASSOCIATED DEEP MIXED CUMULIFORM DEVELOPMENT NOW EVIDENT
ACROSS EASTERN NM/NORTHWEST TX PER VISIBLE SATELLITE IMAGERY.
INCREASING DEEP LAYER WIND FIELD ATOP THE MOIST/UNSTABLE WARM SECTOR
WILL BE HIGHLY FAVORABLE FOR SUPERCELLS WITH AN INCREASING LARGE
HAIL/TORNADO THREAT INTO THIS EVENING. STRENGTHENING LOWER
TROPOSPHERIC WINDS THIS EVENING WILL ACCENTUATE THE RISK OF STRONG
TORNADOES ESPECIALLY ACROSS THE ARKLATEX VICINITY/ADJACENT FAR
SOUTHEAST OK.
..GUYER.. 04/26/2011
ATTN...WFO...JAN...LZK...SHV...TSA...HGX...FWD...OUN...
